The IRS publishes all filing deadlines in
advance for the upcoming year, so you will always know which forms must be
filed and when, and when payments must be made.
In the case of all mid-month (i.e., 15th)
dates, the deadline is extended to the next working day in the event that the
15th falls on a weekend or a federal holiday.
If you are an employee only and do not own
your own business, or rental real estate, or make a lot of money investing,
then you may only need to know about the BIG ONE, April 15th, when
your personal income tax form is due.